Method, system and storage medium for determining the phase of a single layer in a multi-layer coating

Abstract

The present application relates to the technical field of material surface analysis and characterization, and specifically discloses a method and system for determining a single layer phase in a multilayer coating and a storage medium. The method comprises: establishing a layered structure model of the multilayer coating, and setting a physical signal threshold value corresponding to each target single layer; performing thinning treatment on the sample through closed-loop controlled mechanical polishing, monitoring a physical signal of a thinning interface in real time, stopping polishing when the physical signal reaches the threshold value corresponding to the target single layer, and obtaining an exposed target single layer; making a reference mark on the surface of the exposed target single layer, and the mark has a spatial correspondence with a physical signal monitoring area at the time of stopping polishing; transferring the sample with the mark to an analysis device, positioning the sample with the mark, and collecting phase data. The present application can accurately expose the target single layer, avoid over-polishing or under-polishing, realize depth and spatial double verification, and realize non-interfering and traceable phase analysis of the specified single layer.

Description

Technical Field

[0001] This invention relates to the field of material surface analysis and characterization technology, specifically to methods, systems, and storage media for determining single-layer phases in multilayer coatings. Background Technology

[0002] Multilayer coatings (such as thermal barrier coatings, wear-resistant coatings, optical thin films, and semiconductor device thin films) are widely used in modern industry because they can combine the excellent properties of each individual layer. Accurately determining the phase composition, grain orientation, stress state, and other information of each individual layer is crucial for coating design optimization, process control, failure analysis, and performance evaluation.

[0003] Currently, X-ray diffraction (XRD) is the main method for phase analysis of coatings. However, due to the large penetration depth of X-rays, the diffraction signal is a superposition of signals from multiple coating layers, making it difficult to resolve the phase information of a single layer. To address this issue, methods have been developed in this field for testing after layer-by-layer peeling, such as thinning the sample layer by layer through mechanical polishing or ion etching and then sequentially collecting XRD data. However, these methods have significant shortcomings: first, the polishing endpoint is difficult to control precisely, easily leading to over-polishing or under-polishing, resulting in inaccurate exposure of the target interface; second, after the sample is transferred between different devices (such as polishing machines, scanning electron microscopes, and X-ray diffractometers), the microscopic regions cannot be accurately re-located, causing the subsequently measured phase data to mismatch with the actual polished exposure location, resulting in poor reliability of the measurement results; furthermore, this method is destructive and may introduce new stress or phase transitions, altering the original state.

[0004] Therefore, there is an urgent need for a method for determining the phase composition of any single layer in a multilayer coating that can precisely control the thinning endpoint and achieve cross-platform micro-region positioning. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention provides a method, system, and storage medium for determining the phase of a single layer in a multilayer coating. By introducing closed-loop controlled mechanical polishing real-time monitoring, the target single layer can be accurately exposed, avoiding over-polishing or under-polishing. By forcibly associating the monitoring area at the time of polishing cessation with the position of the reference mark, dual verification of depth and space is achieved, thereby enabling non-interference and traceable phase analysis of a specified single layer in a multilayer coating.

[0006] A first aspect of the present invention provides a method for determining a single-layer phase in a multilayer coating, comprising: Establish a layered structure model of the multilayer coating and set the physical signal threshold corresponding to each target single layer; The sample is thinned by mechanical polishing with closed-loop control. The physical signal characterizing the thinned interface is monitored in real time. Polishing is stopped when the physical signal reaches the threshold corresponding to the target monolayer, and the exposed target monolayer is obtained. A reference mark is made on the exposed target monolayer surface, and the mark has a spatial correspondence with the physical signal monitoring area when polishing stops; The sample bearing the label is transferred to the analytical device, where it is located, and phase data is collected.

[0007] Therefore, closed-loop controlled mechanical polishing can accurately expose the target monolayer, avoiding over-polishing or under-polishing. At the same time, a reference mark is made on the exposed surface and a spatial correspondence is established with the monitoring area when polishing stops. This mark can be used to accurately locate the sample before and after transfer, solving the problem of cross-platform micro-area re-search. This ensures that the collected phase data comes from the actual exposed target monolayer, thereby obtaining pure, high signal-to-noise ratio, and high-precision phase information without interlayer aliasing. This significantly improves the accuracy, reliability, and repeatability of monolayer phase determination in multilayer coatings.

[0008] According to an embodiment of the present invention, the above-described measurement method may further include at least one of the following additional technical features: In some embodiments, the physical signal includes an X-ray fluorescence signal; the establishment of a layered structure model of the multilayer coating and the setting of physical signal thresholds corresponding to each target single layer include: Obtain the layer sequence, thickness, and material information of each layer of the multilayer coating, and establish a layered structure model based on the obtained information; The reference sample was polished layer by layer, and the physical signal of each exposed layer was measured as the physical signal threshold of the corresponding target single layer.

[0009] In some embodiments, after the physical signal reaches the threshold corresponding to the target single layer, the absolute value of its rate of change is lower than the preset rate of change upper limit for N consecutive times, triggering a stop polishing process, where N is a positive integer.

[0010] In some embodiments, the reference markers include microscopic pits or protrusions fabricated using focused ion beam or nanoindentation techniques.

[0011] In some embodiments, the analytical apparatus includes an X-ray diffractometer, which acquires the phase data using a grazing incidence mode, and calculates the incident angle of the grazing incidence mode using the following formula: θ = k × arcsin(λ / (2d)); Where θ represents the incident angle, λ is the wavelength of the incident X-ray, d is the interplanar spacing of the target monolayer, and k is a thickness-related correction factor that is 0. <k≤1。

[0012] In some embodiments, the determination method further includes: After collecting phase data, the sample is transferred to a device for making reference marks to verify whether the marks have shifted. If the displacement is less than the preset displacement deviation, the offset is recorded for data correction. If the displacement exceeds the preset displacement deviation, an alarm will be output and the offset will be recorded for data post-processing.

[0013] In some embodiments, when measuring multiple monolayers, the measurement method further includes adaptive iteration, wherein the adaptive iteration includes: Based on the actual phase information or thickness information of the target monolayer that has been measured, the thinning processing parameters of the next target monolayer are dynamically adjusted. Update the layered structure model and repeat the steps of polishing, marking, transferring, and collecting phase data until all target monolayers are measured.

[0014] In some embodiments, the dynamic correction includes at least one of the following: When the deviation between the actual thickness of the measured target single layer and the corresponding thickness in the model exceeds a preset percentage, the thinning depth of the next target single layer is compensated. If the actual phase of the target monolayer contains elements not included in the model, update the feature elements monitored in the next target monolayer. The physical signal attenuation curve of the measured target monolayer is used as a feedforward parameter to adjust the pressure change rate during the polishing of the next target monolayer.

[0015] A second aspect of the present invention discloses a system for measuring a single-layer phase in a multilayer coating for implementing the aforementioned measurement method, comprising: A precision thinning module is used to perform closed-loop controlled mechanical polishing and monitor physical signals in real time; the precision thinning module includes polishing equipment, real-time monitoring sensors, and a controller; A marking module is used to create reference marks, and the marking module and the precision thinning module use the same coordinate system; the marking module includes an observation device capable of creating reference marks and recording their coordinates; An analysis module is used to locate and acquire phase data using the reference markers; the analysis module includes an analysis device and a coordinate verification unit; The main control module is used to set thresholds, control polishing start and stop, execute adaptive iterations, and integrate data.

[0016] Therefore, by integrating the precision thinning module, marking module, analysis module, and main control module, and using the same coordinate system for the marking module and the precision thinning module, the entire process from polishing and thinning, reference marking, to phase analysis is automated and collaborative. The precision thinning module uses real-time monitoring sensors and controllers to automatically stop the polishing process according to a preset threshold, ensuring the precise exposure of the target single layer. The marking module creates a reference mark on the exposed surface and records the coordinates. The analysis module uses this mark to accurately locate and collect phase data in a unified coordinate system. The main control module uniformly sets thresholds, controls the start and stop of polishing, performs adaptive iteration, and integrates data, thereby effectively avoiding interlayer signal aliasing and cross-platform positioning deviations, and improving the efficiency, repeatability, and data traceability of single-layer phase determination of multilayer coatings.

[0017] A third aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the aforementioned measurement method. Thus, the storage medium possesses all the features and advantages of the aforementioned measurement method, which will not be repeated here.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic flowchart of the determination method described in Embodiment 1 of the present invention; Figure 2 This is an SEM image of the layered structure model of Embodiment 1 of the present invention; Figure 3 This is an SEM image of the morphology of the coating before it is polished and peeled off layer by layer as described in Embodiment 1 of the present invention; Figure 4 The image shows the XRD pattern of the coating before it is peeled off layer by layer as described in Embodiment 1 of the present invention. Figure 5 This is an SEM image of the surface morphology of the coating after it has been peeled off layer by layer as described in Embodiment 1 of the present invention. Figure 6 The XRD pattern of the coating after the surface layer is peeled off layer by layer as described in Embodiment 1 of the present invention; Figure 7 This is a SEM image of the surface morphology of the coating after it has been peeled off layer by layer as described in Comparative Example 1 of the present invention. Figure 8 The XRD patterns of the coatings after the surface layers were peeled off layer by layer in Embodiment 1 and Comparative Example 2 of the present invention; Figure 9The image shows the XRD pattern of the coating layer after it was peeled off layer by layer in Comparative Example 3 of this invention. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] In this document, the terms “comprising” or “including” are open-ended expressions, meaning that they include the contents specified in this invention, but do not exclude other aspects.

[0024] In this document, the terms “optionally,” “optionally,” or “optionally” generally refer to an event or condition that may, but may not, occur, and the description includes both cases in which the event or condition occurs and cases in which the event or condition does not occur.

[0025] A first aspect of the present invention provides a method for determining a single-layer phase in a multilayer coating, comprising: Establish a layered structure model of the multilayer coating and set the physical signal threshold corresponding to each target single layer; The sample is thinned by mechanical polishing with closed-loop control. The physical signal characterizing the thinned interface is monitored in real time. Polishing is stopped when the physical signal reaches the threshold corresponding to the target monolayer, and the exposed target monolayer is obtained. A reference mark is made on the exposed target monolayer surface, and the mark has a spatial correspondence with the physical signal monitoring area when polishing stops; The sample bearing the label is transferred to the analytical device, where it is located, and phase data is collected.

[0026] Therefore, this invention creatively combines "closed-loop controlled mechanical polishing for physical thinning" with "cross-platform navigation using reference markers," fundamentally eliminating interlayer signal interference. It constructs a complete, iterative, and data-traceable cross-scale analysis system covering macroscopic polishing, microscopic observation, and micro-area phase analysis, achieving synergistic effects. Specifically: Mechanical polishing with closed-loop control can accurately expose the target monolayer, avoiding over-polishing or under-polishing, ensuring that the signals acquired subsequently come entirely from the target monolayer, resulting in a high signal-to-noise ratio and accurate and reliable phase identification results. Meanwhile, a reference mark is made on the exposed surface and a spatial correspondence is established with the monitoring area when polishing stops. This mark enables precise positioning before and after sample transfer, improving the cross-platform positioning accuracy from the millimeter level (dependent on the macroscopic edge of the sample or manual marking) to the submicron level. This solves the problem of cross-platform micro-area re-search and ensures that the collected phase data comes from the actual exposed target monolayer. This results in pure, high signal-to-noise ratio, and high-precision phase information without interlayer aliasing, significantly improving the accuracy, reliability, and repeatability of monolayer phase determination in multilayer coatings.

[0027] It should be noted that the "closed-loop control" described in this invention refers to: during the mechanical polishing process, by real-time monitoring of physical signals (such as X-ray fluorescence signals) that characterize the coating removal depth, and feeding these signals back to the controller in real time, comparing them with a preset threshold, and dynamically controlling the start-up or shutdown of the polishing equipment or adjusting its parameters based on the comparison results, a closed-loop circuit of "monitoring → comparison → control" is formed.

[0028] Compared to traditional open-loop control (such as fixed-time polishing or fixed-pressure polishing), closed-loop control avoids over-polishing or under-polishing because: over-polishing occurs because under open-loop control, different samples have variations in coating hardness, thickness, polishing slurry state, etc., and fixed parameters cannot adapt to these changes, easily leading to over-polishing and damaging the next layer beneath the target monolayer. Under-polishing is also due to the aforementioned sample differences, making it possible that fixed parameters are insufficient to completely remove the overlay layer above the target monolayer, resulting in the target monolayer not being fully exposed.

[0029] The closed-loop control described in this invention can automatically stop polishing when the physical signal reflecting the remaining thickness reaches a preset threshold, without relying on fixed time or pressure. This threshold corresponds to the characteristic signal plateau when the target single layer is exposed. Therefore, regardless of the differences between samples, the polishing endpoint is determined by the signal itself, rather than preset parameters such as time or pressure, thus avoiding over-polishing and under-polishing.

[0030] Preferably, the mark coincides with the center position of the physical signal monitoring area when polishing stops.

[0031] Therefore, this marker can simultaneously record the polishing endpoint position and the cross-platform positioning origin without the need for additional offset conversion, simplifying the positioning steps and eliminating positioning errors that may be introduced by offset measurement and conversion. This physically unifies the control accuracy in the depth direction and the positioning accuracy in the spatial direction at the same center point, achieving optimal matching of depth-space dual verification, and further improving the accuracy and ease of operation of micro-area re-search.

[0032] In some embodiments, the physical signal includes an X-ray fluorescence signal. Therefore, by utilizing the differences in fluorescence intensity of characteristic elements in different coatings, the interfaces of each coating can be distinguished non-contactly and in real time. This provides a clear and quantifiable basis for setting the threshold of the physical signal of the target single layer and determining the timing of polishing stop, thereby improving the accuracy and reliability of thinning endpoint control.

[0033] In some embodiments, establishing a layered structure model of the multilayer coating and setting the physical signal threshold corresponding to each target single layer includes: The layer sequence, thickness, and material information of each layer of the multilayer coating are obtained, and a layered structure model is established based on the obtained information; specifically, the layer sequence, thickness, and material information of each layer of the multilayer coating are obtained by testing the reference sample, and a layered structure model is established based on the obtained information. The reference sample is polished layer by layer, and the physical signal of each exposed layer is measured as the physical signal threshold of the corresponding target single layer. Specifically, the reference sample is polished layer by layer, and each target single layer is exposed in turn. When each layer is exposed, the physical signal of the target single layer is measured immediately. The measured signal value is used as the physical signal threshold of the target single layer.

[0034] This allows the criterion for stopping polishing to be quantitatively calibrated based on the spectral characteristics of the actual coating, rather than relying on empirical values ​​or fixed parameters. This effectively avoids threshold deviations caused by inaccurate theoretical model parameters (such as absorption coefficient, density, and dopant element distribution), thereby improving the accuracy, specificity, and repeatability of threshold setting and providing a scientific quantitative basis for closed-loop controlled mechanical polishing.

[0035] It should be noted that, in this invention, the reference sample refers to a sample with the same or similar coating structure and preparation process as the sample to be tested, such as samples from the same batch. The layer-by-layer polishing of the reference sample does not rely on any preset signal threshold, but rather identifies the interface by real-time monitoring of the signal change rate. When the signal jumps from one state to another and tends to stabilize, it is considered that the interface has been reached, and the recorded signal strength at this time is the threshold of that layer.

[0036] In some embodiments, a scanning electron microscope (SEM) is used to obtain the thickness information of the multilayer coating to be tested.

[0037] In some embodiments, after the physical signal reaches the threshold corresponding to the target single layer, the absolute value of its rate of change is lower than the preset rate of change upper limit for N consecutive times, triggering a stop polishing process, where N is a positive integer.

[0038] Therefore, it can not only ensure that the physical signal has reached the signal strength range of the target monolayer, that is, the polished surface has reached the expected interface position; it can also effectively avoid false triggering caused by instantaneous signal fluctuations or noise interference. Polishing will only stop when the signal is stable within the threshold range, thereby improving the reliability and accuracy of the polishing endpoint judgment and ensuring that the target monolayer is accurately exposed.

[0039] It should be noted that the rate of change mentioned in this invention refers to the difference in physical signal intensity between adjacent sampling times, and the absolute value of the rate of change is the absolute value of this difference. This parameter is used to characterize the stability of the physical signal; when the signal fluctuation amplitude is less than a preset upper limit, the signal is considered stable.

[0040] Preferably, N is 3 to 5, such as 3, 4, 5, etc.

[0041] In some embodiments, the preset upper limit of the rate of change is determined in the following manner: In the reference sample, after polishing stops at the target layer interface, X-ray fluorescence (XRF) signals are continuously acquired for 10 seconds at a sampling interval of 0.5 seconds, the absolute value of the rate of change between adjacent sampling times is calculated, the maximum value is taken and multiplied by a safety factor, and this value is used as the upper limit of the rate of change.

[0042] Furthermore, the safety factor is 2 to 3, specifically such as 2, 2.2, 2.5, 2.8, 3, etc.

[0043] In some embodiments, the reference markers include microscopic pits or protrusions fabricated using focused ion beam or nanoindentation techniques.

[0044] This enables the fabrication of physical markers with clear geometric features, precise positioning, and stability at the submicron scale. This improves the markers' durability and recognizability, ensuring that they are not easily deformed or lost during cross-platform transfer and observation, and providing a reliable spatial reference for precise cross-platform positioning.

[0045] In some embodiments, the creation of the benchmark markers is performed under SEM.

[0046] In some embodiments, the analytical apparatus includes an X-ray diffractometer, which acquires the phase data using a grazing incidence mode, and calculates the incident angle of the grazing incidence mode using the following formula: θ = k × arcsin(λ / (2d)); Where θ represents the incident angle, λ is the wavelength of the incident X-ray, d is the interplanar spacing of the target monolayer, and k is a thickness-related correction factor that is 0. <k≤1。

[0047] This allows the effective penetration depth of X-rays to match the actual thickness of the target monolayer, thereby enhancing the diffraction signal intensity of the target monolayer while suppressing signal interference from the underlying coating or substrate. The introduction of the correction factor k further considers the influence of thickness variation on the optimal incident angle, improving the accuracy of the grazing incident angle adaptation. This results in diffraction patterns with higher signal-to-noise ratios and clearer phase characteristics, enhancing the accuracy and reliability of monolayer phase analysis in multilayer coatings.

[0048] In some embodiments, positioning with the marker specifically includes: In an X-ray diffractometer, the macroscopic location of the reference mark is found through its optical system; Based on the relative positional relationship between the coordinate system in the X-ray diffractometer and the physical reference mark, the sample is precisely moved so that the X-ray beam irradiates the target micro-region.

[0049] In some embodiments, the determination method further includes: After collecting phase data, the sample is transferred to a device for making reference marks to verify whether the marks have shifted. If the displacement is less than the preset displacement deviation, the offset is recorded for data correction. If the displacement exceeds the preset displacement deviation, an alarm will be output and the offset will be recorded for data post-processing.

[0050] Specifically, when the round-trip verification detects a displacement offset (Δx, Δy), if |Δx| and |Δy| are less than the preset displacement deviation, the offset is automatically added to the coordinates of the subsequent XRD scan, that is, the actual scan center coordinates = original target coordinates + (Δx, Δy). If the offset in any direction exceeds the threshold, the system will output an alarm and record the offset for spatial correction during data post-processing.

[0051] This enables traceable quality control of the cross-platform analysis process, effectively identifying marker position drift caused by factors such as vibration and temperature changes during sample transfer, avoiding mismatch between phase data and target micro-regions due to inaccurate positioning reference; at the same time, the recorded offset can be used for subsequent data correction, ensuring the accuracy and repeatability of the analysis results and improving the reliability of multi-device collaborative measurement.

[0052] In some embodiments, the offset Δz (focus change) in the depth direction is compensated by adjusting the Z-axis sample stage of the XRD, and then the image is scanned after refocusing.

[0053] In some embodiments, when measuring multiple monolayers, the measurement method further includes adaptive iteration, wherein the adaptive iteration includes: Based on the actual phase information or thickness information of the target monolayer that has been measured, the thinning processing parameters of the next target monolayer are dynamically adjusted. Update the layered structure model and repeat the steps of polishing, marking, transferring, and collecting phase data until all target monolayers are measured.

[0054] This effectively compensates for the deviation between the initial model and the actual coating, preventing the accumulation of such deviations in subsequent measurements and thus avoiding greater thinning errors. Simultaneously, the automatic repetition of polishing, marking, and data acquisition steps until all single-layer measurements are completed enables fully automated layer-by-layer analysis of multi-layer coatings, significantly improving measurement efficiency, consistency, and data integrity, while reducing uncertainties introduced by human intervention.

[0055] In some embodiments, the dynamic correction includes at least one of the following: When the deviation between the actual thickness of the measured target layer and the corresponding thickness in the model exceeds a preset percentage, the thinning depth of the next target layer is compensated; specifically, if the measured thickness h1 of the current layer and the model thickness h2 satisfy |h1-h2| / h2>5%, the target exposure depth of the next layer is corrected as follows: h X =h Y +(h1-h2), where h X h represents the target depth for the next layer. Y The thickness of the model in the next layer; When an element not included in the model is present in the actual phase of the measured target layer, the feature elements monitored in the next target layer are updated; specifically, if an element not included in the model is detected in the actual phase of the measured target layer, the element is added to the XRF monitoring element list of the next layer. The physical signal attenuation curve of the measured target single layer is used as a feedforward parameter to adjust the pressure change rate during the polishing of the next target single layer. Specifically, the signal attenuation curve (intensity-time curve) obtained from the current target single layer test is used as feedforward reference data and input into the parameter preset module of the controller before the polishing of the next layer begins, in order to adjust the preset value of the pressure change rate during the polishing of the next layer. If the absolute value of the curve slope is large, the pressure change rate of the next layer is appropriately reduced; conversely, the pressure change rate of the next layer is increased.

[0056] Therefore, on the one hand, by comparing the measured thickness with the model thickness, compensation is made for the thinning depth of the next target single layer when the deviation exceeds a preset percentage. This allows for real-time calibration of the endpoint deviation caused by fluctuations in the actual coating thickness, ensuring the exposure accuracy of each subsequent layer. On the other hand, by detecting the presence of new elements in the measured phase that were not anticipated by the model, the monitored feature elements for the next layer are updated accordingly. This enables adaptive adjustment of signal criteria, avoiding threshold failure due to interference from unknown elements. Furthermore, by recording the attenuation curve of the physical signal during the polishing of the current layer, this curve is fed forward as prior knowledge to the polishing control of the next layer. This allows the controller to predict the signal change trend with thickness reduction in advance, thereby proactively adjusting the pressure change rate at the beginning of the next layer's polishing, avoiding overshoot or oscillation caused by feedback lag. These three methods can be used individually or in combination, enhancing the accuracy and flexibility of adaptive iteration from multiple dimensions. This further improves the reliability and automation level of multilayer coating layer-by-layer measurement, and all logic is automatically triggered by the main control module, requiring no manual input.

[0057] In some embodiments, the feature element includes differential doping elements in the target monolayer or adjacent layers.

[0058] It should be noted that, in this invention, the term "differentiated dopant element" refers broadly to one or more elements present in different layers of a multilayer coating that can produce distinguishable signal differences. Such distinguishable signal differences include, but are not limited to: differences in characteristic X-ray fluorescence intensity, differences in characteristic X-ray fluorescence energy (for different elements), or signal changes caused by matrix effects (absorption, enhancement) resulting from the presence or absence of the element. In other words, as long as the content or state of a certain element (such as boron, silicon, aluminum, titanium, etc.) changes in adjacent coatings, causing a detectable difference in the characteristic X-ray fluorescence signal of that element or other related elements (such as the host element titanium) (e.g., signal intensity exceeding a preset threshold, signal appearance or disappearance), then that element and / or other related elements can be considered differentiated dopant elements of this invention. Those skilled in the art will understand that this definition covers any factors that can lead to distinguishable signal changes, such as element type, concentration, and chemical state, and is not limited to a specific element or a specific doping method.

[0059] A second aspect of the present invention discloses a system for measuring a single-layer phase in a multilayer coating for implementing the aforementioned measurement method, comprising: A precision thinning module is used to perform closed-loop controlled mechanical polishing and monitor physical signals in real time; the precision thinning module includes polishing equipment, real-time monitoring sensors, and a controller; A marking module is used to create reference marks, and the marking module and the precision thinning module use the same coordinate system; the marking module includes an observation device capable of creating reference marks and recording their coordinates; An analysis module is used to locate and acquire phase data using the reference markers; the analysis module includes an analysis device and a coordinate verification unit; The main control module is used to set thresholds, control polishing start and stop, execute adaptive iterations, and integrate data.

[0060] Therefore, by integrating the precision thinning module, marking module, analysis module, and main control module, and using the same coordinate system for the marking module and the precision thinning module, the entire process from polishing and thinning, reference marking, to phase analysis is automated and collaborative. The precision thinning module uses real-time monitoring sensors and controllers to automatically stop the polishing process according to a preset threshold, ensuring the precise exposure of the target single layer. The marking module creates a reference mark on the exposed surface and records the coordinates. The analysis module uses this mark to accurately locate and collect phase data in a unified coordinate system. The main control module uniformly sets thresholds, controls the start and stop of polishing, performs adaptive iteration, and integrates data, effectively avoiding interlayer signal aliasing and cross-platform positioning deviations, and improving the efficiency, repeatability, and data traceability of single-layer phase determination of multilayer coatings.

[0061] In some embodiments, the real-time monitoring sensor in the precision thinning module is an X-ray fluorescence detector.

[0062] In some embodiments, the monitoring area of ​​the X-ray fluorescence detector is always located at the center of the polished area.

[0063] In some embodiments, the main control module includes a data processing system, which has a built-in model generation algorithm based on layer sequence, thickness, and material information. Thus, when the user inputs the thickness and composition of each layer, the data processing system can calculate the theoretical signal intensity range corresponding to each layer according to a preset XRF absorption-enhancement model (basic parameter method) and automatically store it as a threshold.

[0064] A third aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the aforementioned measurement method. Thus, the storage medium possesses all the features and advantages of the aforementioned measurement method, which will not be repeated here.

[0065] The present invention will be explained below with reference to embodiments. Those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0066] Example 1 This embodiment uses a boron-doped titanium carbonitride (B) multilayer composite coated cutting tool of grade A as an example to describe in detail the implementation process of the present invention. The multilayer composite coating is a known four-layer structure, consisting of the following layers from the surface to the bottom: a B-containing surface layer (first layer), a first B-containing intermediate layer (second layer), a second B-containing intermediate layer (third layer), and a B-free bottom layer (fourth layer).

[0067] To accurately determine the phase composition of each monolayer and investigate the existence forms of boron and its influence on the Ti(C,N) lattice, a method for determining the phase composition of monolayers in multilayer coatings is provided, such as... Figure 1 As shown, it includes: Step 1: Pre-analysis and model building A blade with coating grade A, produced in the same batch as the sample to be tested, was used as a reference sample. Scanning electron microscopy (SEM) confirmed its four-layer structure, with the thickness of each layer shown in Table 1. Data was automatically transmitted, and the main control module automatically established a system based on the acquired information. Figure 2 The initial layered structure model is shown; the reference sample is precisely polished layer by layer, and the characteristic fluorescence signal of Ti element is measured with an XRF detector immediately after each layer is exposed. The average value is taken at 5 different locations, and the signal intensity of each layer is recorded as the physical signal threshold corresponding to each layer, as shown in Table 1.

[0068] Table 1. Information on each layer and physical signal thresholds of multilayer composite coated cutting tools of grade A.

[0069] The obtained initial layered structure model is used as the target basis for subsequent precise thinning. The threshold of the physical signal (XRF signal of Ti element) corresponding to each layer is stored in the controller and used as one of the stopping criteria for mechanical polishing in subsequent closed-loop control.

[0070] Step 2: Precise thinning process with closed-loop control The sample to be tested, bearing this grade, was placed on an automated polishing machine equipped with an XRF detector (SEM and grazing-incidence XRD tests were performed before polishing, such as...). Figures 3-4 As shown, the polishing machine has a closed-loop control circuit, including polishing equipment, real-time monitoring sensors and controller; the current target single layer is set as the first boron-containing intermediate layer (second layer), and its predetermined exposure depth is about 5.7 μm (i.e. the first layer needs to be removed); mechanical polishing is performed using a 1 μm diamond suspension, and the Ti element characteristic fluorescence signal of the polished surface is monitored in real time using an XRF detector during the polishing process; Initially, because the boron-containing surface layer (the first layer) covers the target monolayer, the Ti signal is in the high-intensity signal range. As polishing progresses, the boron-containing surface layer gradually thins until it is completely removed, and the Ti signal intensity drops to the medium-intensity signal range. During this process, the controller receives the XRF signal in real time and compares it with the threshold stored in step 1. Polishing is triggered to stop when the following two criteria are met simultaneously: 1) The XRF signal reaches the threshold corresponding to the target single layer; 2) The absolute value of the XRF signal change rate is lower than the preset upper limit of change rate for five consecutive times. The preset upper limit of change rate is determined as follows: In the reference sample, after polishing stops at the target layer interface, XRF signals are continuously collected for 10 seconds (sampling interval 0.5 seconds), the absolute value of the change rate between adjacent sampling times is calculated, the maximum value is taken and multiplied by a safety factor (usually 2-3) as the upper limit of change rate. In this embodiment, the upper limit of change rate is set to 50 cps / s. Subsequent measurements confirmed that the total remaining coating thickness was approximately 16.6 μm when polishing stopped, meaning that approximately 5.7 μm had been precisely removed, successfully exposing the second surface layer. Simultaneously with the stop of polishing, the controller recorded the center coordinates of the XRF monitoring area as a reference for the subsequent fabrication of reference markers.

[0071] Step 3: Creation of Microscopic Reference Markers and Coordinate Markers After mechanical polishing, the sample was cleaned and placed in the primary observation device—SEM—for testing. The results are as follows: Figure 5 As shown, the current exposed surface is confirmed to be the first boron-containing intermediate layer (second layer), with a smooth surface and no over-polishing marks. Near the target analysis area coinciding with the center position of the XRF monitoring area in step 2, a micro-pit with distinct geometric features is fabricated using a focused ion beam (FIB) or nanoindentation apparatus as a reference marker. In the SEM system coordinate system, the center coordinates (0,0) of this reference marker are recorded, along with the offset (ΔX, ΔY) of the target analysis micro-area relative to this reference marker. Simultaneously, the polishing stop monitoring center position coordinates recorded in step 2 are compared with the center coordinates of the reference marker to verify that the overlap deviation is less than 1 μm.

[0072] Step 4: Micro-area phase collection based on reference markers The sample bearing the reference mark is transferred to the second analytical device—XRD. First, the microscopic pit marks on the sample are located using the optical microscope integrated with the XRD (macroscopic positioning); then, based on the offset (ΔX, ΔY) recorded in step 3, the X-ray beam spot is precisely moved to the target micro-region using a high-precision motorized sample stage (accuracy ±0.5μm); the XRD is set to grazing incidence (GIXRD) mode, and the grazing incidence angle is dynamically calculated using the following formula based on the second layer thickness (approximately 5.6μm) detected in step 1: θ = arcsin(λ / (2d)) × k, where λ is the incident X-ray wavelength (Cu target, 1.5406 Å), d is the interplanar spacing of Ti(C,N) (approximately 2.16 Å), and k is 0.8; The calculated incident angle is approximately 10° to match the thickness of the second layer and suppress interference from signals in the lower layers (third, fourth, and substrate). A scan is performed within a 2θ range of 20° to 90° to obtain... Figure 6 The diffraction pattern shown.

[0073] After XRD data acquisition, the sample was transferred back to the SEM. The same reference marker was repositioned under the SEM to verify whether it had shifted or deformed after the two transfers. The measurement showed that the marker position offset was 0.8 μm, which is less than the preset deviation threshold (1.5 μm). No alarm was required, but this offset was automatically added to the coordinates of subsequent XRD scans for data correction.

[0074] Step 5: Phase Identification and Data Integration Figure 6 The strongest peak corresponds to the (111) and (200) crystal planes of cubic Ti(C,N). Compared with the standard PDF card (No. 42-1488), all Ti(C,N) diffraction peaks show a systematic shift to higher angles. According to Bragg's law (2dsinθ=λ), the shift to higher angles indicates a decrease in interplanar spacing d and a contraction of the lattice constant. This phenomenon is highly consistent with the lattice distortion effect caused by the substitution of some C / N positions by B atoms (atomic radius 0.088nm) in the Ti(C,N) lattice (Ti atomic radius 0.147nm, C / N atomic radius approximately 0.077nm). No independent TiB2 characteristic peaks were found in the spectrum.

[0075] Therefore, the phase identification result is: the phase of the second layer is a cubic Ti(C,N) solid solution with B solid solution. This phase information, actual polishing depth (5.68μm), reference marker coordinates (0,0), offset (ΔX,ΔY), and interface morphology diagram are integrated and updated into the layered structure model.

[0076] Step 6: Adaptive Iterative Analysis Based on the analysis results of the second layer, the system automatically performs adaptive iterative corrections without manual intervention. 1) Thickness compensation: The measured thickness of the second layer is 5.68μm, which deviates from the initial thickness (5.6μm) in step 1 by +1.4%. Within the preset tolerance (±5%), there is no need to compensate for the predetermined polishing depth of the next layer. 2) Phase update: It was confirmed that element B exists in solid solution form and is not an independent TiB2 phase. Therefore, the characteristic monitoring element of the third layer (intermediate layer 2) remains Ti, and there is no need to update the monitoring element list. 3) Feedforward compensation: The measured signal attenuation curve of the second layer is used as the control reference for the next round of polishing to reduce the overshoot during the third layer polishing.

[0077] The system automatically updates the initial layered structure model, recalculates the physical signal threshold (I3) of the third layer, and sets the predetermined stop criterion for the next round of polishing as the monitoring of the Ti element fluorescence signal decreasing from I2 to I3. Steps 2 to 5 are repeated to sequentially measure the second boron-containing intermediate layer (third layer) and the boron-free bottom layer (fourth layer). The phase analysis results show that boron exists in solid solution form in the Ti(C,N) lattice throughout the coating, without forming an independent boride phase; as the boron content decreases, the Ti(C,N) lattice constant gradually increases (approaching the boron-free standard value of 4.260 Å), confirming the lattice shrinkage effect caused by boron solid solution.

[0078] Example 2 This embodiment uses the analysis of a silicon (Si)-doped titanium carbonitride multilayer composite coated cutting tool of grade B as an example to describe in detail the implementation process of the present invention. The coating has a known four-layer structure, consisting of, from top to bottom: a silicon-containing surface layer, a first Si-containing intermediate layer, a second Si-containing intermediate layer, and a Si-free bottom layer.

[0079] To accurately determine the phase composition of each monolayer and investigate the existence form of Si and its influence on the Ti(C,N) lattice, a method for determining the phase composition of monolayers in multilayer coatings is provided. Except for the sample, steps 1, 3, 4, and 5 in this embodiment are the same as those in Example 1, but steps 2 and 6 differ from those in Example 1, as detailed below: Step 2: Precise thinning process with closed-loop control The sample was placed on an automated polishing machine equipped with an XRF detector. The target monolayer was set as the first Si-containing intermediate layer (second layer), with a depth of approximately 3.0 μm. Polishing was performed using a 1 μm diamond suspension. During the polishing process, the XRF detector monitored the characteristic fluorescence signal of titanium in real time after polishing. When the controller detected that the Ti element signal intensity dropped from I1' to a preset threshold I2', it automatically triggered the polishing machine to stop. Measurements confirmed that approximately 3.0 μm had been precisely removed, leaving a total coating thickness of approximately 9.0 μm, successfully exposing the second layer surface.

[0080] Step 6: Adaptive Iterative Analysis The rest of the process is the same as in Example 1, except that the predetermined stopping criterion for the next round of polishing is changed to monitor the Ti element fluorescence signal as it drops from I2' to I3'.

[0081] Example 3 This embodiment uses the analysis of a titanium carbonitride aluminum (Al) doped cemented carbide multilayer composite coated cutting tool of grade C as an example to describe in detail the implementation process of the present invention. The coating has a known four-layer structure, which consists of, from the surface to the bottom: an aluminum-containing surface layer, a first Al-containing intermediate layer, a second Al-containing intermediate layer, and an Al-free bottom layer.

[0082] To accurately determine the phase composition of each monolayer and investigate the existence form of Al and its influence on the Ti(C,N) lattice, a method for determining the phase composition of monolayers in multilayer coatings is provided. Except for the sample, steps 1, 3, 4, and 5 in this embodiment are the same as those in Example 1, but steps 2 and 6 differ from those in Example 1, as detailed below: Step 2: Precise thinning process with closed-loop control The sample was placed on an automated polishing machine equipped with an XRF detector. The target monolayer was set as the first Al-containing intermediate layer (second layer), with a depth of approximately 4.0 μm. Polishing was performed using a 1 μm diamond suspension. During the polishing process, the XRF detector monitored the characteristic fluorescence signal of titanium (Ti) in real time after polishing. When the controller detected that the Ti element signal intensity dropped from I1'' to the preset threshold I2'', it automatically triggered the polishing machine to stop. Measurements confirmed that approximately 4.0 μm had been precisely removed, leaving a total coating thickness of approximately 12.0 μm, successfully exposing the second layer surface.

[0083] Step 6: Adaptive Iterative Analysis The rest of the process is the same as in Example 1, except that the predetermined stopping criterion for the next round of polishing is changed to monitor the Ti element fluorescence signal as it drops from I2'' to I3''.

[0084] Comparative Example 1 This comparative example is based on Example 1, and differs from Example 1 only in that the polishing method in step 2 is different. In Example 1, step 2 employs closed-loop control: the XRF detector monitors the Ti signal in real time, and automatically stops when the signal reaches a preset threshold I2 and the rate of change is below 50 cps / s for 5 consecutive times; This comparative example uses the traditional fixed-time polishing method: based on preliminary experiments, the average time required to remove the first layer (approximately 5.7 μm) was determined to be T(20 s). All samples were then polished for T(20 s) before stopping, without real-time XRF monitoring. The results are as follows: Figure 7 As shown.

[0085] like Figure 7 As shown, due to slight differences in coating hardness and polishing environment among different batches of samples, the fixed-time method results in low accuracy in controlling coating thickness. Measurements of 10 parallel samples show that the deviation in the target remaining thickness has increased from submicron level (<±0.3μm) in Example 1 to ±2μm. Some samples exhibit over-polishing (damaging the next layer) or under-polishing (the surface layer is not completely removed), which directly affects the accuracy of subsequent phase analysis.

[0086] Comparative Example 2 This comparative example is based on Example 1, differing only in that: no physical reference marks were made on the exposed target layer surface in step 3. After transferring the sample from SEM to XRD, the operator could only rely on accidental macroscopic scratches on the sample edges or surface for rough positioning, resulting in the following... Figure 8 As shown.

[0087] like Figure 8 As shown, due to the inability to accurately reproduce the target micro-region (X,Y) under SEM, the X-ray beam spot position deviates randomly. Ten independent localizations and measurements of the same target layer revealed that the signal-to-noise ratio of the target layer's characteristic peaks (such as the shifted peaks of B-Ti(C,N) solid solution) in the XRD pattern decreased by an average of about 35%, and occasional interference peaks from adjacent regions or scratch contaminants appeared, indicating a significant reduction in the accuracy and repeatability of the phase detection results.

[0088] Comparative Example 3 This comparative example is based on Example 1, differing only in that: in the XRD test, the grazing incidence mode is not used, but a conventional symmetric Bragg-Brentano diffraction mode is used, and the results are as follows. Figure 9 As shown.

[0089] like Figure 9As shown, because the penetration depth of the conventional XRD mode is much greater than the thickness of the target layer (5.6 μm), the acquired diffraction signals are mixed with strong diffraction peaks from the third and even fourth layers below. The characteristic diffraction peaks of the target layer (second layer), especially the small angular shift peaks caused by boron solid solution, are severely covered or submerged by the main peaks of the lower layers, making it difficult to accurately identify the true phase and lattice parameters of the second layer, and significantly reducing the accuracy of phase identification.

[0090] In the description of this specification, the references to terms such as "an embodiment," "some embodiments," "a method of implementation," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0091] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for determining a single-layer phase in a multilayer coating, characterized in that, include: Establish a layered structure model of the multilayer coating and set the physical signal threshold corresponding to each target single layer; The physical signals include X-ray fluorescence signals; The process of establishing a layered structure model of the multilayer coating and setting the physical signal threshold corresponding to each target single layer includes: acquiring the layer sequence, thickness and material information of each layer of the multilayer coating, and establishing a layered structure model based on the acquired information; polishing the reference sample layer by layer, and measuring the physical signal of each exposed layer as the physical signal threshold of the corresponding target single layer. The sample is thinned by mechanical polishing with closed-loop control. The physical signal characterizing the thinned interface is monitored in real time. Polishing is stopped when the physical signal reaches the threshold corresponding to the target monolayer, and the exposed target monolayer is obtained. A reference mark is made on the exposed target monolayer surface, and the mark has a spatial correspondence with the physical signal monitoring area when polishing stops; The sample bearing the mark is transferred to the analytical device, where it is located, and phase data is collected. When there are multiple target single layers, the method further includes adaptive iteration, which includes: Based on the actual phase information or thickness information of the target monolayer that has been measured, the thinning processing parameters of the next target monolayer are dynamically corrected; the layered structure model is updated, and the steps of polishing, marking, transfer, and collecting phase data are repeated until the measurement of all target monolayers is completed. The dynamic correction includes at least one of the following: When the deviation between the actual thickness of the measured target single layer and the corresponding thickness in the model exceeds a preset percentage, the thinning depth of the next target single layer is compensated. If the actual phase of the target monolayer contains elements not included in the model, update the feature elements monitored in the next target monolayer. The physical signal attenuation curve of the measured target monolayer is used as a feedforward parameter to adjust the pressure change rate during the polishing of the next target monolayer.

2. The determination method according to claim 1, characterized in that, When the physical signal reaches the threshold corresponding to the target single layer, the absolute value of its rate of change is lower than the preset rate of change upper limit for N consecutive times, triggering a stop polishing process, where N is a positive integer.

3. The determination method according to claim 1, characterized in that, The reference markings include microscopic pits or protrusions fabricated using focused ion beam or nanoindentation techniques.

4. The determination method according to claim 3, characterized in that, The analytical equipment includes an X-ray diffractometer, which acquires the phase data using a grazing incidence mode, and calculates the incident angle of the grazing incidence mode using the following formula: θ = k × arcsin(λ / (2d)); Where θ represents the incident angle, λ is the wavelength of the incident X-ray, d is the interplanar spacing of the target monolayer, and k is a thickness-related correction factor that is 0. <k≤1。 5. The determination method according to claim 1, characterized in that, Also includes: After collecting phase data, the sample is transferred to a device for making reference marks to verify whether the marks have shifted. If the displacement is less than the preset displacement deviation, the offset is recorded for data correction. If the displacement exceeds the preset displacement deviation, an alarm will be output and the offset will be recorded for data post-processing.

6. A system for determining a single-layer phase in a multilayer coating for implementing the determination method according to any one of claims 1 to 5, characterized in that, include: A precision thinning module is used to perform closed-loop controlled mechanical polishing and monitor physical signals in real time; The precision thinning module includes polishing equipment, real-time monitoring sensors, and a controller; A marking module is used to create reference marks, and the marking module and the precision thinning module use the same coordinate system; the marking module includes an observation device capable of creating reference marks and recording their coordinates; An analysis module is used to locate and acquire phase data using the reference markers; the analysis module includes an analysis device and a coordinate verification unit; The main control module is used to set thresholds, control polishing start and stop, execute adaptive iterations, and integrate data.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the measurement method according to any one of claims 1 to 5.

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